Method of making bags having folded bases, and bags so made

ABSTRACT

In the manufacture of paper or plastics bags with folded bases from multi-ply flattened tube sections, the ends of the tube sections are opened by suction means applied to the outermost ply of at least one wall of the tube sections at locations where all except the innermost ply have been provided with air holes or incisions.

I Mar. 12, I974 Unite States atent 1 Kuckhermann References Cited UNITED STATES PATENTS l2/l940 l l/l971 FOLDED BASES, AND BAGS SO MADE [75] Inventor: Gustav Kuckhermann, Lcngerich of 2,224,656 Robinson...........,............ 93/28 Westphalia, Germany 3,618,476 3,446,121 3,272,093

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5/1969 9/1966 Brockmuller.......

[73] Assignee: Windmoller & Holscher,

Westphalia, Germany May 30, 1972 Appl. No.1 257,892

Primary ExamincrRoy Lake [22} Filed:

Assistant Examiner.lames F. Coan Attorne Agent, or FirmFleit, Gipple & Jacobson [57] ABSTRACT In the manufacture of paper or plastics bags with Germanym.........,............. 2128264 7 v folded bases from multi-ply flattened tube sections, 93/35 R, 93/8 W, 93/28,

nHe 0 .m .m H e O wnws y m b e dm lm. nm w flm O h e l. d rp 3 tnd SSO.I nO uV m m nricp CCO em n 5 Le 6 m b u t e o w tfl mwwy h n. D- Df. S U atm& n5 en mr m.w f B t tmolmc 32 8 6MB IQ 2 2w2 R l F3 4 20 m 9%5 4 WW 9 .R "m5 2 WW m w U m w uh "m H moo Q2 S, n :14 C '02 dy S t d9 U I .F m Hod 5 55 W 3 Claims, 8 Drawing Figures METHOD OF MAKING BAGS HAVING FOLDED BASES, AND BAGS SO MADE The invention relates to a method of making bags with folded bases from multi-ply flattened tube sections of paper or the like, in which the ends of the tubesections are opened by suction tools applied to the outermost ply of at least one wall of the tube sections and the bases are subsequently folded.

The so-called pre-opening of the bag ends before the bags are open fully is usually effected by pairs of suckers or suction beams which are applied to both faces near the ends of the flattened tube sections and then moved apart. Since the plies of each wall of a tube section are interconnected near the ends of the tube section by so-called transverse adhesive which may be formed by dabs of adhesive applied in rows transversely to the length of the bag section, all the plies of the bag section are pre-opened and not just the outermost ply. In the case of bags made from tube sections in which the plies are coterminous, the transverse adhesive is also necessary to obtain the required security of the cross-bottom or block-bottom folded bases. For bags in which the ends of the plies are staggered, transverse adhesive is not required, at least not in the region of the side flaps of the folded bases because the staggering of the plies of the side flaps ensures that the plies are stuck together by the adhesive that is normally applied at the base.

Accordingly, in the manufacture of bags with staggered plies the transverse adhesive in the vicinity of the side flaps of the folded base serves solely to facilitate proper opening of the ends of the tube sections. The additional expense of adhesive applicators and the adhesive itself is therefore incurred only in order to achieve proper opening of all the plies in the case of these bags. Further, the need for transverse adhesive calls for prolonged interruption in the manufacturing process between the time the tube sections are made on a tube-drawing machine and when the tube sections are processed by base-laying equipment because the adhesive must be given time to set so that the plies do not come apart when the tube sections are pre-opened. Such interruptions are costly in the case of base-laying equipment which is automatically fed with tube sections.

The invention aims to make it possible to use suction for the pre-opening of folded tube sections even before the adhesive has 'set or if there is no adhesive at all, thereby saving the expense of adhesive and adhesive applicators or at least ensuring that preopening and full opening of the ends of the tubesections and folding of the bases can be effected immediately following production of the tube sections.

According to the invention, there is provided a method of making bags having a folded base from multi-ply flattened tube sections of paper or the like, wherein the ends of the tube sections are opened by suction tools applied to the outermost ply of at least one wall of the tube sections and the bases are subsequently folded, all except the innermost ply of said wall being provided with air holes prior to the opening step at a location where the suction tools are applied. The air holes may be in the form of perforations, incisions or cut-outs. The suction applied by the suction tools will therefore be effective right through the outer plies up to the innermost ply so that the atmospheric pressure inside each tube section will press the innermost ply against the suction tool and all the plies will be preopened without the need for adhesive.

As in the case of transverse perforations or scorelines that are formed to facilitate severing of the tube sections, the air holes in the outer plies for the purpose of the present invention may be formed before the individual plies are brought together to form a multi-layer web which is then brought to a tubular form. Of course in this case the air holes in each ply will be applied at a spacing and sequence corresponding to the desired disposition of the holes in the finished tube sections. This will ensure that the parts of each tube section which are permeable to air will assume the desired locations in the finished tube sections.

In the case of bags in which the ends of the plies of a first wall of each tube section are staggered inwardly of the tube section and the ends of the plies of a second wall of each tube section are staggered outwardly of the tube section, the suction tools for opening the ends of the tube sections are in each case preferably applied to the said first wall near the edge of the innermost ply and further suction tools are provided for application to the outermost ply of said first wall near the edge of the outermost ply. It will then be sufficient that for the second wall of each tube section suction tools be applied to near the edge of the innermost ply backing onto the said further suction tools, the suction tools that are applied to the first wall near the edge of the innermost ply being backed by a counterbearing such as a flat plate which may be movable in unison therewith. The means for producing the air holes may be sets of needles, knives or stamping tools which, as in the case of the tools that are used for producing transverse scorelines, are rotatable at a peripheral speed corresponding to the feeding speed of the plies on which they act. It is particularly advantageous if the air holes are in the form of stellular incisions because such incisions define three or more flaps which are readily deflected to permit the air between the plies to be sucked off.

Examples of the invention will now be described with reference to the accompanying diagrammatic drawings in which:

FIG. 1 is a cross-sectional view of a bag section taken on the line 1-1 in FIG. 2;

FIG. 2 is a fragmentary plan view of a flattened bag section in which the plies of each' wall are coterminous;

FIGS. 3 to 5 are fragmentary enlarged details of modified bag sections;

FIGS. 6 and 8 are side elevations of two kinds of apparatus for forming the bag sections, and

FIG. 7 is a cross-section corresponding to FIG. 1 but of a tube section in which the ends of the plies are staggered.

Referring to FIGS. 1 and 2, a flattened tube section which is open at an edge 1 consists of two side walls 2 and 3, each of which is formed from five outer plies 4- and an innermost ply 5. All except the innermost plies 5 are provided with perforations 6 at a location where suckers 7 are later applied as indicated in chain-dotted lines for the purpose of opening the bag section. In this way the suction effect extends through the plies 4 up to the innermost ply 5. Consequently, the atmospheric pressure between the plies S is effective to press all the plies against the respective suckers 7 which, when moved in the direction of the arrows 8, will open all the plies of the tube section.

In the case of FIGS. 1 and 2, the perforations 6 are actually stamped out of the ply material whereas in FIG. 3 holes 9 are formed such as by needles, in FIG. 4 there are air holes in the form of straight incisions l and in FIG. 5 stellular incisions 11 are provided. The FIG. 5 embodiment is particularly advantageous because the incisions define triangular flaps which are readily deflectable to permit the passage of air therethrough.

As shown in FIG. 6, the air holes in the form of stamped out apertures, needle perforations or incisions can be provided in webs l3 and 14 which are destined to form the staggered outer plies of a three-ply tube section at the same stations 16 and 17 where transverse perforations or scorelines are formed in the webs to facilitate subsequent separation of the tube sections from one another. The transverse perforations or scorelines for severing purposes are formed by tools indicated at 18, the air-holes being formed by tools 19 located on both sides of the tools 18. The transverse perforating or scoring station for the ply 12 which is destined to form the innermost ply of each tube section is of course not provided with air hole-forming tools 19. In the illustrated example, the tools 18 and 19 are carried by rotary cylinders whereby during each rotation of the cylinders the respective plies l3 and 14 are formed with air holes at locations corresponding to the trailing end of one tube section and the leading end of the next following tube section.

In the case of FIG. 8, tube sections are being formed in which the plies are coterminous and in which trans verse perforations or scorelines are therefore not necessary to facilitate subsequent severing of the tube sections from one another. Again, the tube sections are made from three plies 20-, 21 and 22 of which the ply 20 will form the innermost ply. The outer plies 21 and 22 are simultaneously provided with air holes by tools 24 carried by a single rotary cylinder 23. All the plies are brought together at a location 25. Longi'tudinally extending strips of adhesive are applied by an applicator 26 and the composite web 27 passes to a tubeforming station 28 whereafter the tube is severed into sections 29 at a transverse severing station (not shown). The air holes formed in the plies 21, 22 by the tools 24 are indicated in the severed and flattened tube section 29 to an exaggerated scale at 30, 31, 32 and 33; these air holes permit subsequent opening of all the plies of the tube section even though there is no transverse adhesive.

FIG. 7 indicates how a tube section having staggered plies is pre-opened. The tube section has a first wall 35 in which the ends of the plies 39, 40, 41 are staggered internally of the tube section and a second wall 34 in which the'ends of the plies are staggered externally of the tube section. Suckers 36 and 37 applied to the upper edge of the tube section will engage only the respective longest plies 38 and 39. Since the plies 40 and 41 do not underlie the suckers 37, no air holes are formed in the ply 39 at its upper edge. In the absence of transverse adhesive, the plies 40 and 41 would therefore not be opened by the suckers 37. Consequently, suckers 42 overlying air holes 43 in the plies 39 and 40 are applied near the edge of the innermost ply 41. The suckers 36 backing the suckers 37 are adequate to ensure opening of all the plies of the second wall of the tube section. A counterbearing for the suckers 42 is provided by a flat plate 44 which is moved away from the suckers 42 at the same time as the suckers 36 and 37 are moved apart.

The invention extends to multi-ply bags made by the method as hereinbefore described.

I claim: V

1. A method of making bags having a folded base from multi-ply flattened tube sections of paper or the like, wherein the ends of the tube sections are opened by suction tools applied to the outermost ply of at least one wall of the tube sections and the bases are subsequently folded, all except the innermost ply of said wall being provided with air holes prior to the opening step at a location where the suction tools are applied.

2. A method according to claim 1 for making bags in which the ends of the plies of a first wall of each tube section are staggered inwardly of the tube section and the ends of the plies of a second wall of each tube section are staggered outwardly of the tube section, wherein said suction tools are applied to said first wall near the edge of the innermost ply and further suction tools are applied to the outermost ply of said first wall near the edge of the outermost ply.

3. A method according to claim 1, wherein the air holes are in the form of stellular incisions. 

1. A method of making bags having a folded base from multi-ply flattened tube sections of paper or the like, wherein the ends of the tube sections are opened by suction tools applied to the outermost ply of at least one wall of the tube sections and the bases are subsequently folded, all except the innermost ply of said wall being provided with air holes prior to the opening step at a location where the suction tools are applied.
 2. A method accOrding to claim 1 for making bags in which the ends of the plies of a first wall of each tube section are staggered inwardly of the tube section and the ends of the plies of a second wall of each tube section are staggered outwardly of the tube section, wherein said suction tools are applied to said first wall near the edge of the innermost ply and further suction tools are applied to the outermost ply of said first wall near the edge of the outermost ply.
 3. A method according to claim 1, wherein the air holes are in the form of stellular incisions. 